Paints and stains are often used to protect and decorate a variety of substrates. In comparison to paints, stains may be transparent or semitransparent suspensions of colorants in carrier liquids, and are typically designed to color a substrate without hiding it under an opaque film. Some stains are formulated to impart or transport the colorants into the pores of the substrate rather than creating a film on top of the substrate surface. As a result, the stained substrate is colored, but the grain pattern is generally not hidden. In contrast, paints are usually opaque solutions or suspensions of colorants in a carrier, which are designed to hide or cover a surface with an opaque film.
One problem with stains is that many substrates, such as wood substrates, may include soft and/or porous regions that may not be readily visible until a stain is applied. The colorants of conventional stains tend to soak into these regions, which may preferentially darken such regions due to the increased concentration of the colorants. This can result in a sharp color contrast to the remaining surface of the substrate, referred to as “ticking” While this contrast may be desirable for some applications, many consumers prefer a more uniform distribution of stain colorants. Thus, there is an ongoing need for stain compositions that may reduce color contrasts in porous substrates, such as wood substrates.